| Summary: | 博士 === 國立交通大學 === 機械工程系所 === 101 === The tube spinning process is a metal forming process used in the manufacture of axisymmetric products, and has been widely used in various applications. In this study, the neck-spinning process was applied to form the neck part of the tube end at elevated temperatures. Finite element analysis (FEA) has been successfully applied to the tube spinning processes, but no temperature effects have been considered on neck-spinning process. For this reason, the objective of this dissertation is to introduce finite element analysis into investigation of tube neck-spinning process at elevated temperatures.
To construct a comprehensive finite element model for tube neck-spinning process at elevated temperatures, this study firstly performed isothermal hot compression tests over a wide range of strain (0.05-0.8), temperatures (873-1273 K), and strain rates (0.001-50 s-1), since the material is sensitive to strain rates at high temperatures. Tube neck-spinning experiments were then performed and the finite element analysis with the same process variables was also conducted by using commercial finite element software, Abaqus/Explicit. Comparisons between experimental and simulation results on thickness distribution and the outer contour of the spun tube were discussed. During the final steps, the average deviations between the simulation and experiment were 8.94% in thickness and 1.4% in outer contour. The simulation results corresponded well with those derived from the experiment.
Finally, the verified finite element model for tube neck-spinning process at elevated temperatures was used to investigate the influences of two process parameters: the roller feeding pitch and the roller forming path. The roundness of the spun tube became worse and the roller reaction forces increased as the roller feeding pitch increased. For the roller forming path, the thickness distribution of the spun tube formed by curved paths was determined to be more uniform than that of the spun tube formed by straight paths.
|
|---|
